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STEEL CASTINGS.
417
test was round in every case, and gave slightly worse results than a flat, but this is far from explaining the great inferiority of .the casting when compared with the preliminary test, or the more marked difference from what should be expected in rolled steel of similar tensile strength.
'   TABLE XX-B. Annealed Bars from Castings of Medium Hard Steel.
Manufactured by The Pennsylvania Steel Company.
						••S	2			
						Jc8	<3		a    -	i^
						M§,	o<	ri <M V	£	1C a
jj	Composition; percent.					J>*	..aa	5S	*	b"
1								«&		•§
H						*	8 "	o .	g-»	8
§						•sf .	sij	4^ 09	J3 « 00	o .
0						Ill	111	§rt	3 (4	•fid S «> ^ o
										
w	C.	Mn.	P.	S.	SI.	p	»	i	On	S
						60580	88710	80.50	88.57	55.6
						00680	82380	86.50	61.90	53.4
021	.20	.64	.020	.022	.30	00880	82760	86.00	44.34	63.8
						01480	80740	82.00	89.80	60.0
						02420	82460	88.00	50.90	62.0
						03820	87400	86.00	40.83	69.1
						04880	84170	24.50	28.57	62.T
953	.22	.56	.035	.034	.80	05500 05845	44850 83595	29.00 20.00	89.40 82.40	68.5 61.0
						65980	82290	80,00	83.87	49.0
						07010	48630	26.00	82.40	72.8
974	.88	.75	.029	.028	.85	72630 75240	4494.0 45880	16.00 28.00	20.70 81.68	61.9 61.0
006	.85	.63	.038	.084	.84	78090 75160	45890 45510	rr.so	21.25 27.04	62.1 60.6
The results show what has been mentioned before—that the ultimate strength and elastic limit are altered very little by the amount of work as long as the piece is not finished at a low temperature. In the annealed casting the elastic limit is 56.63 per cent, of the ultimate strength, while in the annealed bars rolled from the ingot it is 57.39 per cent. This approximation is remarkable because the factors relating to ductility show that the physical state of the two metals must be radically different.
SEO. XXg.—Medium hard steel castings.—It has been shown that the average elastic ratio in annealed castings is about the same as in annealed rolled bars, but there will be greater variations between individual tests in the case of the unworked metal owing to local imperfections, and there will be greater variations with a stronger steel. This will be shown by Table XX-B, which gives the results on duplicate bars from four different heats of harder metal.